Abstract: Sir—David Sack and colleagues' instruction to "learn to co-exist with the vibrios" (Jan 17, p 223),1 although sensible from a microbiological viewpoint, is intolerable from a public-health perspective. Cholera epidemics are a sensitive marker of severe underdevelopment.2 Occurrence of large-scale or recurrent epidemics accurately identifies communities with limited access to safe water, poor hygiene, and inadequate sanitation.